This invention relates to automotive vehicles which are arranged to be powered by electrical energy and also energy from internal combustion engines, and more particularly to such vehicles wherein the drive can be provided either by electric motors energized from batteries, or else by gasoline or similar engines, or both.
Heretofore there have been numerous proposals for eliminating the pollution caused by automobiles driven by internal combustion engines. All-electric cars and trucks were produced and used many years ago, these being powered by electric motors connected with storage batteries that were periodically recharged. More recently, various more sophisticated types of cars have been proposed and produced, utilizing electric power that is supplemented by internal combustion engines. In many such cases the recharging of the batteries was done by a generator driven by the internal combustion engine. In some of these prior hybrid-power automobiles the internal combustion engine was also utilized for driving purposes, being coupled to the rear wheels through a transmission which was likewise utilized either in whole or in part to carry the power of the electric motor drive.
In my issued patent above identified there is disclosed and claimed a hybrid-powered unit for driving automobiles, wherein one and the same electrical machine is used as the driving motor and also as the generator for recharging the batteries. For the latter use the electrical machine is mechanically driven by the internal combustion engine.
The usual procedure, where electrical drives are incorporated, is to use a series-type motor which has a desirably high starting torque. While this is of great advantage, it entails very high starting currents which give rise to difficulties of control. Moreover, the extremely high starting currents necessitate oversized equipment, including brushes, commutator, magnet iron, copper conductors and the like. These prior arrangements all contemplated power transmissions between the electric motor and the wheels, which were incapable of extremely high ratios and ranges. Thus the large size and weight of the electric power equipment, and the complexity of the current control devices for the electric motor constituted severe drawbacks which prevented widespread adoption of electric vehicle power. Moreover, in most cases the use of electric power did not in itself have a capability of higher vehicle speeds.